On Monday, Dave Furukawa, who is visually impaired, was walking his young son to school along with Simon. As the trio crossed Brownwood Avenue, witnesses saw a car run a stop sign and strike the 80-pound boxer, then Furukawa.

Bystanders have told the Furukawa family that Simon's protective instinct kicked in, despite injuries that would prove to be fatal.

"What people have said is that Simon either got up or jumped out, and pushed my son out of the path of the car," said Furukawa, who has counted on Simon as his companion and guide for the past four years. "This is true loyalty and courage."

Witnesses lifted Furukawa's 4-year-old son, Will, and took him to his mother. Simon went with them.

"Broken leg, gash on his side and internal bleeding, but he followed us home," said Furukawa. "Once he was sure Will was OK, he laid down."

Family members rushed Simon to an emergency vet clinic, but the boxer died on the way.

Furukawa was hospitalized with a broken elbow, knee and heel.

Atlanta police say Calvin Armour was cited for running a stop sign and failing to yield to pedestrians in the crosswalk.

Columbus, Ohio-based Pilot Dogs, which provided Simon to Furukawa, has said it will give Furukawa another trained guide dog.